This application is related to U.S. patent application Ser. No. 09/583,858, filed May 31, 2000 entitled xe2x80x9cControl System And Process For Automatically Controlling Agitator Motion Patterns In A Washing Machinexe2x80x9d, by Alfredo Diaz Fernandez et al, filed concurrently with the present application, assigned to the same assignee of the present invention and herein incorporated by reference.
The present invention is generally related to washing machines and, more particularly, to a process and system for selectively controlling agitator motion patterns, and water level in the washing machine.
Use of electronic controllers in washing machines have allowed to provide agitator control techniques that in varying degrees have partially addressed some relatively narrow needs. For example, U.S. Pat. No. 4,779,431 purports that an agitator drive that produces sinusoidal agitator motion in a washing machine, as opposed to square wave type of motion, results in somewhat improved wash action.
U.S. Pat. Nos. 4,542,633 and 4,554,805 disclose an agitator drive system that uses a rotational angle detector. Both of such patents appear to be limited to providing a fixed agitator stroke angle at a fixed rate of strokes/min, independently of the type of load or articles to be cleansed.
None of the foregoing controllers allow the washing machine for selectively controlling the agitator motion pattern so that the agitator motion pattern, e.g., angle of travel of the agitator and/or strokes/min of the agitator can be selectively adjusted to reflect a desired agitator motion pattern based on the specific characteristics of the articles to be cleansed, such as the type of fabric of the articles, the level of dirtiness of such articles, etc. In addition, none of the foregoing controllers, allow for implementing agitator control techniques by measuring predetermined inertial characteristics of the agitator that allow for selectively adjusting the water level of the washing machine based on the true needs of a given washing or rinsing cycle. In view of the above, it would be desirable to provide a control system and techniques for selectively controlling the agitator motion pattern based on the characteristics of the articles or load to be cleansed, as indicated by the user. It would also be desirable to adapt the same techniques to adjust the water level of the washing machine so that inexpensively and reliably the user of the washing machine is able to conserve a valuable natural resource, i.e., water, while at the same time ensuring that no fabric damage occurs due to inappropriate load density in a given washing cycle.
Generally speaking, one embodiment of the present invention fulfills the foregoing needs by providing a process for automatically controlling water-level in a washing machine having a motor drive coupled to energize a motor that drives the agitator. The process allows for selecting a target water level based on one or more water-level selection signals. The method further allows for measuring a parameter indicative of the water level based on an actual inertial response of the agitator. A comparing step allows for comparing the actual agitator inertial response against a target agitator inertial response, and a selecting step allows for selectively actuating one or more water valves for allowing passage of water so as to adjust the water level of the washing machine based on deviations between the actual agitator inertial response and the target agitator inertial response.
Another embodiment of the present invention further fulfills the foregoing needs by providing a control system for automatically controlling water-level in a washing machine having a motor drive coupled to energize a motor that drives the agitator. The system comprises a selecting module configured to select a target water level based on one or more water-level selection signals. The system further comprises a measuring module configured to measure a parameter indicative of the water level based on an actual inertial response of the agitator. A comparing module is configured to compare the actual agitator inertial response against a target agitator inertial response, and an actuating module is configured to selectively actuate one or more water valves for allowing passage of water so as to adjust the water level of the washing machine based on deviations between the actual agitator inertial response and the target agitator inertial response.
In yet another embodiment, the present invention fulfills the foregoing needs by providing a washing machine programmed for automatically controlling water-level in a tub for receiving articles to be washed. The washing machine comprises a motor that drives the washing machine""s agitator. The washing machine further comprises a motor drive coupled to energize the motor and one or more water valves responsive to a respective actuating signal for passing water into the tub. A controller is coupled to the one or more water valves to supply the respective actuating signal. The controller in turn comprises a selecting module configured to select a target water level based on one or more water-level selection signals. The controller further comprises a measuring module configured to measure a parameter indicative of the water level based on an actual inertial response of the agitator. A comparing module is configured to compare the actual agitator inertial response against a target agitator inertial response, and an actuating module is configured to generate the respective actuating signal supplied to the one or more water valves to adjust the water level of the washing machine tub based on deviations between the actual agitator inertial response and the target agitator inertial response.